Cloud texture is difficult to determine in channel 5 imagery. Low clouds and fog rarely show up in this channel because the temperature difference in the land and cloud is typically small. Care should be used when assuming that the indicated temperature of the ground should equal the actual surface observation temperature. Because the satellite actually senses the ground skin temperature, and not the temperature several feet off the ground, differences of 5 to 10 degrees are not uncommon. Finally, for thin clouds, some radiation from lower levels will also be detected, and this results in some error in the estimation of the temperature of the cloud.